<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="/vue2/js/vue.js"></script>
    <script src="com.js"></script>
</head>
<body>

    <div id="app">

        <div>{{firstVal}}</div>

        <my-com2 v-bind:param1="firstVal"></my-com2>

    </div>

    <script>
        var vm = new Vue({
            el:"#app",
            data:{
                firstVal:"ab"
            }
        });
    </script>
</body>
</html>